drivers/input/keyboard/gpio_keys.c

   1 /*
   2  * Driver for keys on GPIO lines capable of generating interrupts.
   3  *
   4  * Copyright 2005 Phil Blundell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/version.h>
  13
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irq.h>
  18 #include <linux/sched.h>
  19 #include <linux/pm.h>
  20 #include <linux/sysctl.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/delay.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/input.h>
  25 #include <linux/gpio_keys.h>
  26
  27 #include <asm/gpio.h>
  28
  29 static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
  30 {
  31         int i;
  32         struct platform_device *pdev = dev_id;
  33         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
  34         struct input_dev *input = platform_get_drvdata(pdev);
  35
  36         for (i = 0; i < pdata->nbuttons; i++) {
  37                 struct gpio_keys_button *button = &pdata->buttons[i];
  38                 int gpio = button->gpio;
  39
  40                 if (irq == gpio_to_irq(gpio)) {
  41                         unsigned int type = button->type ?: EV_KEY;
  42                         int state = (gpio_get_value(gpio) ? 1 : 0) ^ button->active_low;
  43
  44                         input_event(input, type, button->code, !!state);
  45                         input_sync(input);
  46                 }
  47         }
  48
  49         return IRQ_HANDLED;
  50 }
  51
  52 static int __devinit gpio_keys_probe(struct platform_device *pdev)
  53 {
  54         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
  55         struct input_dev *input;
  56         int i, error;
  57
  58         input = input_allocate_device();
  59         if (!input)
  60                 return -ENOMEM;
  61
  62         platform_set_drvdata(pdev, input);
  63
  64         input->evbit[0] = BIT(EV_KEY);
  65
  66         input->name = pdev->name;
  67         input->phys = "gpio-keys/input0";
  68         input->dev.parent = &pdev->dev;
  69
  70         input->id.bustype = BUS_HOST;
  71         input->id.vendor = 0x0001;
  72         input->id.product = 0x0001;
  73         input->id.version = 0x0100;
  74
  75         for (i = 0; i < pdata->nbuttons; i++) {
  76                 struct gpio_keys_button *button = &pdata->buttons[i];
  77                 int irq = gpio_to_irq(button->gpio);
  78                 unsigned int type = button->type ?: EV_KEY;
  79
  80                 set_irq_type(irq, IRQ_TYPE_EDGE_BOTH);
  81                 error = request_irq(irq, gpio_keys_isr, IRQF_SAMPLE_RANDOM,
  82                                      button->desc ? button->desc : "gpio_keys",
  83                                      pdev);
  84                 if (error) {
  85                         printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n",
  86                                 irq, error);
  87                         goto fail;
  88                 }
  89
  90                 input_set_capability(input, type, button->code);
  91         }
  92
  93         error = input_register_device(input);
  94         if (error) {
  95                 printk(KERN_ERR "Unable to register gpio-keys input device\n");
  96                 goto fail;
  97         }
  98
  99         return 0;
 100
 101  fail:
 102         for (i = i - 1; i >= 0; i--)
 103                 free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
 104
 105         input_free_device(input);
 106
 107         return error;
 108 }
 109
 110 static int __devexit gpio_keys_remove(struct platform_device *pdev)
 111 {
 112         struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
 113         struct input_dev *input = platform_get_drvdata(pdev);
 114         int i;
 115
 116         for (i = 0; i < pdata->nbuttons; i++) {
 117                 int irq = gpio_to_irq(pdata->buttons[i].gpio);
 118                 free_irq(irq, pdev);
 119         }
 120
 121         input_unregister_device(input);
 122
 123         return 0;
 124 }
 125
 126 struct platform_driver gpio_keys_device_driver = {
 127         .probe          = gpio_keys_probe,
 128         .remove         = __devexit_p(gpio_keys_remove),
 129         .driver         = {
 130                 .name   = "gpio-keys",
 131         }
 132 };
 133
 134 static int __init gpio_keys_init(void)
 135 {
 136         return platform_driver_register(&gpio_keys_device_driver);
 137 }
 138
 139 static void __exit gpio_keys_exit(void)
 140 {
 141         platform_driver_unregister(&gpio_keys_device_driver);
 142 }
 143
 144 module_init(gpio_keys_init);
 145 module_exit(gpio_keys_exit);
 146
 147 MODULE_LICENSE("GPL");
 148 MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
 149 MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");